<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>事件驱动和数据驱动</title>
</head>

<body>
    <div>
        <div>商品数量<input id="goodsnum" /></div>
        <div>商品价格<input id="goodsprice" /></div>
        <div>小计<span id="total"></span></div>
    </div>

</body>
<script>
    let goodsnumInput = document.getElementById("goodsnum");
    let goodspriceInput = document.getElementById("goodsprice");
    let totalSpan = document.getElementById("total");

    goodsnumInput.oninput = function () {
        totalSpan.innerHTML = goodsnumInput.value * goodspriceInput.value;
    }

    goodspriceInput.oninput = function () {
        totalSpan.innerHTML = goodspriceInput.value * goodsnumInput.value;
    }







</script>

</html>